While the Red Sox are clearly in the market for a reliever, which would represent a more attractive target?

The Red Sox have been without a closer for this season, and it has bitten them hard. Brandon Workman has blown 4 of his 9 save opportunities, Matt Barnes has blown 6 of his 10 opportunities, and Brasier has blown 3 of his 10 chances. The Red Sox are reportedly front-runners for Mets closer Edwin Diaz, and are also in on Blue Jays closer Ken Giles. However, the Mets have been said to be demanding an even higher price than they paid for him this offseason. According to Buster Olney, the Mets want one of the Red Sox two best prospects(MLB.com), Bobby Dalbec or Triston Casas. Which arm is the better option for the Red Sox, Diaz or Giles?

Giles will obviously come at a cheaper price, because he is a free agent after the 2020 season, and is not as big of a name as Diaz. Giles is a hard throwing reliever who can reach 100 mph, but has never been an all-star or won any awards. He was on the World Series Champion Astros team in 2017, and is famous for punching himself in the face after a blown save. He will turn 29 at the end of the season, and next year will be his last year of arbitration. Diaz was an all-star in 2018, and also received MVP and Cy Young votes last year. He too, is a hard throwing right hander, and was traded to the Mets from the Mariners this offseason. Edwin Diaz is under control for three more seasons after this one. While Diaz’s name has been mentioned in countless headlines over the last two years, Giles has flown under the radar for the last few years. Trading for Diaz would sell jerseys and tickets, while a Giles trade might not even make blockbuster headlines. However, a look at their statistics shows that the Red Sox should strongly consider trading for Giles instead of Diaz.

Below is an ERA / BABIP / FIP chart for Diaz and Giles. BABIP stands for “batting average on balls in play”. An average pitcher’s BABIP should sit at .300, and if it is higher it is because he has experienced bad luck, lower if he has experienced good batted ball luck (a top pitcher’s BABIP should be a little lower, around .280 due to the fact that he induces weaker contact). FIP calculates what a pitcher’s ERA would be if he had average batted ball luck (The fact that Giles has a high BABIP but similar ERA and FIP could be explained by the fact that he has stranded lots of runners this year). 


20172.30 / .292 / 2.393.27 / .238 / 4.02
20184.65 / .333 / 3.081.96 / .281 / 1.61
20191.54 / .348 / 1.604.95 / .398 / 3.83

Diaz is only 25, and as he enters his prime it is possible that he fixes his shortcomings and is consistently able to pitch like he did last year. However, that is quite an expensive gamble to make. Giles is more consistent. Even in his “down season” last year, he was hampered by bad batted ball luck, and actually pitched decently well.

Stats like BABIP and FIP ignore how hard opposing batters hit the ball off of a pitcher though. Here are Giles and Diaz’s hard hit% / barrel% over the last three seasons:

201733.8% / 4.2%33.8% / 4.5%
201836.0% / 6.6%35.3% / 3.8%
201933.8% / 7.0%45.0% / 6.9%

While Giles is better at limiting hard-hit balls, Diaz tends to miss the barrel more. Overall, it’s hard to say one has a significant advantage over the other on balls in play.

While Diaz has great potential and would stay with the Sox through 2022, he would cost at least one of the Red Sox best minor leaguers. Also, elite performance from him is no guarantee. On the other hand, Ken Giles is a proven AL East performer, is more affordable, and will allow the Red Sox to be confident that they have a top level closer both this year and next year. As the trade deadline approaches, we can only hope that Dombrowski goes after Giles, not Diaz.

While there is rumor that the Ken Giles is hampered by elbow inflammation, and the Red Sox may not be interested in spending to get Diaz, they are the two most logical fits for the defending champions and it’s worth discussing.